Field of the Invention
The present invention relates to an ink, an ink cartridge including the ink, and an image recording method using the ink.
Description of the Related Art
In image recording methods, inks containing self-dispersing pigments as coloring materials have been conventionally used for the purpose of improving the optical density of images. In particular, self-dispersing pigments having a phosphonic acid group bonded directly or via another atomic group to the surfaces thereof (hereinafter also referred to simply as “phosphonic acid-type self-dispersing pigments”) are known to easily provide images having high color development.
However, inks containing self-dispersing pigments disadvantageously provide images with low scratch resistance although such inks provide images with relatively high color development. Therefore, an attempt to improve the scratch resistance of images has been made by further adding polyurethane resin particles to an ink containing a self-dispersing pigment (Japanese Patent Laid-Open No. 2013-253236). In Japanese Patent Laid-Open No. 2013-253236, an ink containing a phosphonic acid-type self-dispersing pigment and polyurethane resin particles is described.